You can use either, the difference is the formula weight, due to the different number of hydrates. Ferric ammonium sulfate X hydrate (FAS, for short) is a great salt for this analysis. To determine how much FAS you need for a 1000 ppm solution (1g/L), use the atomic weight of iron divided by your salt formula weight. This gives you the fraction of the salt that is Fe. Set that equal to the mass of Fe you want divided by X. Solve for X and that is what you need to weigh out.

Essentially, the equation should look like this:

(Fe/FAS) = (n/X)

This generally will work for making a ppm solution of any type where the mass you want is only one part of the compound you are working with. The salt/compound weight should always be larger than the mass you want of the one ion.

dear friend

the preparation of Fe standard is very simple we have numerous procedure for that, but what is the state of the iron Fe 2+ or Fe 3+, i will explain both.

for Fe 3+ determination the sulphosalicylic and thiocyanide method is their. for sulphosalicylic method weigh about 0.8635 g of ammonium ferric sulphate and dissolved in 5 ml of con sulphuric acid and made up with DD water in 100ml Std flask, that solution contains 1000 ppm of iron. from that stock you have to diiluted for furthur dilutions. iron solution pipetted out into 50 ml of Std flask 15 ml of amonium hdroxide and ammonium chloride buffer and 5 ml of 10% sulphosalicylic acid, after that the solution stand for 10 min, the yellow colour is developed. you have to measure the absorbance at 425nm.

in thiocyanide method u have follow the procedure

Principle

Thiocyanate ions react with iron(III) ions in solution to form an intense red coloured complex ion:

colorimeter and suitable filter (blue) - a solution of the complex displays maximum absorption at 480 nm,

potassium thiocyanate containing 250 mg dm−3 thiocyanate (250 ppm) (30 cm3), iron(III) chloride solution 0.41 mol d−3 (70 cm3), solution of unknown thiocyanate concentration (10 cm3)

Method

Care: Wear eye protection. Iron(III) chloride solution is an irritant.

1. Fill three burettes, one with the potassium thiocyanate solution containing 250 ppm thiocyanate, one with deionised water and one with iron(III) chloride solution.

2. Add 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 cm3 of the potassium thiocyanate solution to six 100 cm3 volumetric flasks A-F. Add deionised water to bring the volume in each flask to about 80 cm3.

3. To each flask add 10 cm3 iron(III) chloride solution and then add deionised water to bring volume to 100 cm3. Mix the solutions thoroughly.

Flask

4. Measure the absorbance of each solution using a colorimeter.

5. Plot a graph of absorbance (y axis) against thiocyanate concentration (in ppm thiocyanate) (x axis) for the six solutions.

6. Add 10 cm3 of the solution of unknown thiocyanate concentration to a 100 cm3 volumetric flask and add deionised water to bring the volume in the flask to about 80 cm3.

7. Add 10 cm3 iron(III) chloride solution to the flask and then add deionised water to bring volume to 100 cm3 and mix the solution thoroughly.

8. Measure the absorbance of the solution using a colorimeter.

9. Use the graph to find the concentration of thiocyanate ions as ppm thiocyanate in the unknown solution.

In this method u have to use the Amm.Ferric sulphate standard also instead of iron chloride.

For detrmination of Fe2+

we have 1,10 Phenanthroline method, u have to see in the web.. u will get the procedure..

I have used the 1,10-orthophenanthroline method, and it works extremely well. You need to be sure to convert all the Fe to Fe(II) for it to work best. It works as Fe(III), but the color is much less intense.

As for the standard solution, what Fe compound are you using? You want 1g. Fe per L of water (1000g solvent). Just figure out what fraction of your compound is iron, and use that ratio to calculate the mass of the compound you need.

Thanks Shanmugam and Crew, I will follow your method for preparation but what about 510 nm wavelength is it wrong wavelength for Iron I have specord 50( analytikjena ) , about the web , I asked you because I found many papers and Methods for Iron determination and I need Experience one to get the best way

510 nm is the best for the phenanthroline method for analysis of Fe(II). This is the one we use in the analytical teaching labs, because it is easy, and doesn't take long to do. Do make sure to keep your standards at high concentrations for color development, then dilute to volume. It doesn't work as well if you dilute it first.

Totally agree with all above^^

thanks Crew, could you give me a step sequence of Fe(II) determination, kindly in sequence steps

Also, I have ammonium ferric sulphate.12H2O, Dose it differ from the ammonium ferric sulphate.6H2O and what about the Kits

Chalermporn Thongpoon, Elizabeth Crew, Shanmugam ss

You can use either, the difference is the formula weight, due to the different number of hydrates. Ferric ammonium sulfate X hydrate (FAS, for short) is a great salt for this analysis. To determine how much FAS you need for a 1000 ppm solution (1g/L), use the atomic weight of iron divided by your salt formula weight. This gives you the fraction of the salt that is Fe. Set that equal to the mass of Fe you want divided by X. Solve for X and that is what you need to weigh out.

Essentially, the equation should look like this:

(Fe/FAS) = (n/X)

This generally will work for making a ppm solution of any type where the mass you want is only one part of the compound you are working with. The salt/compound weight should always be larger than the mass you want of the one ion.

Hi, The answers given are perfect and fully self explanatory. However for more information you can go for the book written by F. D. Snell for Photometric and fluorometric analysis of many metals.

you directly by 1000ppm concentration in market or use FAS to prepare the 1000ppm concentrations.

I am fully agreed with the answers given earlier by Dr Elizabeth Crew

Ahmed, I suggest weight 1 g of Iron metalic (sponge or other) disolve with acid and bring to 1000 ml with water destilled and deinized, yous have 1000 mg/L or 1000 ppm of Fe, and then you measurement any method your prefered. Regards.

Dear ahmed.1000ppm means 1000mg/lL.You should calculate the molecular weight of ex Cl3Fe with or without water and there is only 56 my of Fe in it.to have 1000 mg of Iron how many gram of FeCl3 you needed.Weight it and dissolve it in one lit of water.

I agree with Elizabeth, but I go for Cristian's as it is direct. You need your pure metallic iron which you dissolve in nitric acid ;until it dissolves then tpo up in a litre with distilled or deionised water. this is your 1000ppm.

I agree with Cristian, that the best method is to dissolve metallic iron in acid (preferably in nitric). Some time ago I dealt with interferences from iron ions in voltamperometry of heavy metal ions. In voltamperometry such action is the best. I think that in spectrophotometry it also should be good.

Can anybody help me to figure out how can I prepare Fe(II) standard from 1000ppm standard Fe solution. I am using Ferrozine methos. What I did, I took 2.5, 5.0, 7.5, 10, 12.5 and 15 micro liter of 1000 ppm standard Fe solution and added with 1 ml ferrozine, wait for 30 mins., centrifuge at 10000g and measured absorbance by spectrophotometer at 562nm. However, the plot did not show a good linearity, although R2 value is about 0.945. Is there any flaws in my measurement. Could anybody kindly suggest me? Any help will be highly appreciated. 

how do i prepare a standard Iron III Chloride solution which contains 0.00195g/mL Fe?

Dear Ahmed Mahfouz

i think you got the sufficient result for preparation of  Iron standard, But u have to use the spectrophotometric method using 1, 10 phenanthroline method is one of the best method to determination of iron (II). Because it is very easy to prepare the solution,  complexation and everything.. So u have try to use that method for determination...

I am determining Ferrous and Ferric iron species(Fe-2 and Fe-3) by Colorimetric method termed 1,10-Phenanthroline. I am getting the higher absorbance(0.100-0.500) for total iron standards and even samples than the Ferrous ion standards and samples which absorbance is less (0.020- 0.040). But when I put the absorbance in regression equation, the reading of Ferrous iron in comparison of Total Iron goes on higher side which absorbance was less than Total Iron. I have performed the analysis and calculation many times but unable to resolve this issue. If some scientist has the expertise of this method, He may please guide me as my research is stuck for months. Thanks

Ferrozine reagent is also useful

Dear dr Ahmed

i hope this pdf will be helpful for you

Guide To Preparation of Stock Standard Solutions

Best regards